\name{anno_block}
\alias{anno_block}
\title{
Block annotation
}
\description{
Block annotation
}
\usage{
anno_block(gp = gpar(), labels = NULL, labels_gp = gpar(),
    labels_rot = ifelse(which == "row", 90, 0),
    labels_offset = unit(0.5, "npc"), labels_just = "center",
    which = c("column", "row"), width = NULL, height = NULL, show_name = FALSE,
    graphics = NULL)
}
\arguments{

  \item{gp}{Graphic parameters.}
  \item{labels}{Labels put on blocks.}
  \item{labels_gp}{Graphic parameters for labels.}
  \item{labels_rot}{Rotation for labels.}
  \item{labels_offset}{Positions of the labels. It controls offset on y-directions for column annotation and on x-directoin for row annotation.}
  \item{labels_just}{Jusification of the labels.}
  \item{which}{Is it a row annotation or a column annotation?}
  \item{width}{Width of the annotation. The value should be an absolute unit. Width is not allowed to be set for column annotation.}
  \item{height}{Height of the annotation. The value should be an absolute unit. Height is not allowed to be set for row annotation.}
  \item{show_name}{Whether show annotatio name.}
  \item{graphics}{A self-defined function that draws graphics in each slice. It must have two arguments: 1. row/column indices for the  current slice and a vector of levels from the split variable that correspond to current slice. When \code{graphics} is set, all other graphics parameters in \code{\link{anno_block}} are ignored.}

}
\details{
The block annotation is used for representing slices. The length of all arguments should be 1 or the number of slices.
}
\value{
An annotation function which can be used in \code{\link{HeatmapAnnotation}}.
}
\seealso{
\url{https://jokergoo.github.io/ComplexHeatmap-reference/book/heatmap-annotations.html#block-annotation}
}
\examples{
Heatmap(matrix(rnorm(100), 10), 
    top_annotation = HeatmapAnnotation(foo = anno_block(gp = gpar(fill = 2:4),
        labels = c("group1", "group2", "group3"), labels_gp = gpar(col = "white"))),
    column_km = 3,
    left_annotation = rowAnnotation(foo = anno_block(gp = gpar(fill = 2:4),
        labels = c("group1", "group2", "group3"), labels_gp = gpar(col = "white"))),
    row_km = 3)

# =============  set the graphics argument ==============
col = c("1" = "red", "2" = "blue", "A" = "green", "B" = "orange")
Heatmap(matrix(rnorm(100), 10), row_km = 2, row_split = sample(c("A", "B"), 10, replace = TRUE)) + 
rowAnnotation(foo = anno_block(
	graphics = function(index, levels) {
		grid.rect(gp = gpar(fill = col[levels[2]], col = "black"))
		grid.text(paste(levels, collapse = ","), 0.5, 0.5, rot = 90,
			gp = gpar(col = col[levels[1]]))
	}
))

labels = c("1" = "one", "2" = "two", "A" = "Group_A", "B" = "Group_B")
Heatmap(matrix(rnorm(100), 10), row_km = 2, row_split = sample(c("A", "B"), 10, replace = TRUE)) + 
rowAnnotation(foo = anno_block(graphics = function(index, levels) {
	grid.rect(gp = gpar(fill = col[levels[2]], col = "black"))
	grid.text(paste(labels[levels], collapse = ","), 0.5, 0.5, rot = 90,
		gp = gpar(col = col[levels[1]]))
}))

Heatmap(matrix(rnorm(100), 10), row_km = 2, row_split = sample(c("A", "B"), 10, replace = TRUE)) + 
rowAnnotation(foo = anno_block(
	graphics = function(index, levels) {
		grid.rect(gp = gpar(fill = col[levels[2]], col = "black"))
		txt = paste(levels, collapse = ",")
		txt = paste0(txt, "\n", length(index), " rows")
		grid.text(txt, 0.5, 0.5, rot = 0,
			gp = gpar(col = col[levels[1]]))
	},
	width = unit(3, "cm")
))
}
